Method, apparatus and system for establishing a connection

ABSTRACT

A method for establishing a connection includes the following steps: A mobility management entity generates a create bearer context request message and sends the message to a selected serving gateway. The create bearer context request message at least includes address information of at least one packet data network gateway and corresponding indication information of the protocol type of connection establishment. The serving gateway receives and analyzes the create bearer context request message, and determines the protocol type of the connection according to the indication information of the protocol type of connection establishment. The serving gateway processes the create bearer context request message with the determined protocol type of connection. Further provided are a mobility management entity, a serving gateway, and a network system which are able to reduce time delay when connection is established.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/CN2008/071158, filed May 31, 2008, which claims priority toChinese Patent Application No. 200710028575.4, filed Jun. 14, 2007, andChinese Patent Application No. 200710165080.6, filed Nov. 7, 2007, allof which are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to system architecture evolution (SAE),and more particularly to a method, an apparatus, and a system forestablishing a connection among gateways.

BACKGROUND OF THE INVENTION

In order to increase the competitiveness of future mobile networks, the3rd generation partnership project (3GPP) is researching a futurenetwork architecture. The network architecture includes an SAE at anetwork side and an evolved universal terrestrial radio access network(E-UTRAN) (i.e., LTE) at a wireless side. The structure of an evolvedpacket system (EPS) is as shown in FIG. 1, and includes at least threelogical function entities, i.e., a mobility management entity, a servinggateway, and a packet data network gateway. The mobility managemententity is in charge of mobility management of control-plane, whichincludes management of user context and mobility status, temporary useridentity assignment, security function, etc. The serving gateway is amobile anchor point for local inter base station handover and inter 3GPPaccess system handover, and is in charge of managing and storing IPbearer parameters and network routing information, lawful interception,etc. The packet data network gateway is a gateway towards the externalnetwork, and is in charge of realizing policy-based management,user-based packet filtering, accounting, lawful interception, user IPaddress assignment, etc., and therefore serves as a user-plane anchorpoint among different access systems. Subscription information of usersis stored in a home subscriber server (HSS).

A protocol used for an interface between the serving gateway and thepacket data network gateway may be the general packet radio service(GPRS) tunneling protocol (GTP), or the proxy mobile IP protocol (PMIP).

Although manners for establishing connections by using differentprotocols are defined in different transfer services (TS) respectively,in a process of practical network deployment and upgrade, the servinggateway may support multiple connection protocols (for example, the GTPand the PMIP) at the same time, while the packet data network gatewayonly supports one of them (for example, the GTP). Under this situation,a connection between the serving gateway and the packet data networkgateway is usually established by using the following manners.

The serving gateway uses one connection protocol to initiate aconnection establishment request to the packet data network gateway.When the packet data network gateway does not support such a protocol,no response is received. After timeout, the serving gateway considers touse another connection protocol again to initiate the connectionestablishment request. When implementing the present invention, theinventor discovers a disadvantage of such a manner if the connectionprotocol selected by the serving gateway first time is a connectionprotocol not supported by the packet data network gateway, a time delaywhen the connection is established successfully will be extended.

Or, the serving gateway may use multiple protocols supported by theserving gateway at the same time to initiate the connectionestablishment request to the packet data network gateway. The packetdata network gateway selects one or all of the protocols for responsesaccording to its own ability. The serving gateway selects one responsemessage that first reaches to establish a connection. When implementingthe present invention, the inventor of the present invention discovers adisadvantage of such a manner for a serving gateway that supportsmultiple protocols, more processing is required. Also, such a mechanismthat a sender sends multiple messages of the same function but withdifferent protocols regardless of the ability of the receiver willconsume more processing resources.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a method, an apparatus, anda system for establishing a connection, which are able to reduce a timedelay when a connection is established successfully.

In an embodiment, the present invention provides a method forestablishing a connection. The method includes the following steps.

A create bearer context request message is generated.

The create bearer context request message is sent to a selected servinggateway.

The create bearer context request message includes address informationof at least one packet data network gateway and corresponding indicationinformation of the protocol type of connection establishment.

In another embodiment, the present invention provides a method forestablishing a connection. The method includes the following steps.

The create bearer context request message is received and analyzed, sothat the address information of the packet data network gateway andcorresponding indication information of the protocol type of connectionestablishment are obtained.

A protocol type of connection for establishing a connection with thepacket data network gateway is determined according to the analyzedindication information of the protocol type of connection establishment.

The create bearer context request message is processed according to thedetermined protocol type of connection.

In yet another embodiment, the present invention provides a method forestablishing a connection. The method is implemented in a system whichincludes at least a mobility management entity, a serving gateway, and apacket data network gateway. The method includes the following steps.

The mobility management entity generates a create bearer context requestmessage and sends the request message to a selected serving gateway. Thecreate bearer context request message includes address information of atleast one packet data network gateway and corresponding indicationinformation of the protocol type of connection establishment.

The serving gateway analyzes the create bearer context request message,and determines the protocol type of connection for establishing aconnection with the packet data network gateway according to thecorresponding indication information of the protocol type of connectionestablishment.

The serving gateway processes the create bearer context request messagecorrespondingly according to the determined protocol type of connectionestablishment.

In another embodiment, the present invention provides a mobilitymanagement entity. The mobility management entity includes a packet datanetwork gateway information acquisition unit and a bearer establishmentinitiation unit.

The packet data network gateway information acquisition unit is adaptedto obtain address information of the packet data network gateway andcorresponding indication information of the protocol type of connectionestablishment.

The bearer establishment initiation unit is adapted to generate a createbearer context request message and send the message to a selectedserving gateway, wherein the create bearer context request messageincludes address information of at least one packet data network gatewayand the indication information of the corresponding protocol type ofconnection establishment.

In yet another embodiment, the present invention provides a servinggateway. The serving gateway includes a reception and analysis unit, aprotocol type determination unit, and a bearer establishment processunit.

The reception and analysis unit is adapted to receive and analyze acreate bearer context request message to obtain address information of apacket data network gateway and indication information of thecorresponding protocol type of connection establishment.

The protocol type determination unit is adapted to determine theprotocol type of connection for establishing a connection with thepacket data network gateway according to an analyzed result of thereception and analysis unit.

The bearer establishment process unit is adapted to process the createbearer context request message accordingly according to the protocoltype of connection determined by the protocol type determination unit.

In yet another embodiment, the present invention provides a networksystem. The network system includes at least a mobility managemententity, a serving gateway, and a packet data network gateway.

The mobility management entity is adapted to generate a create bearercontext request message and send the message to a selected servinggateway, wherein the create bearer context request message includes atleast one address information of the packet data network gateway andindication information of the corresponding protocol type of connectionestablishment.

The serving gateway is adapted to analyze the create bearer contextrequest message from the mobility management entity, determine theprotocol type of connection establishing a connection with the packetdata network gateway according to the indication information indicatingthe protocol type of connection establishment, and process the createbearer context request message correspondingly according to thedetermined protocol type of connection.

In view of the above, according to the embodiments of the presentinvention, when the mobility management entity requests to establish aconnection with a selected serving gateway, address information of apacket data network gateway may be indicated and the serving gateway maybe instructed to obtain the protocol type of connection supported by thepacket data network gateway. Thus, the serving gateway may select theprotocol supported by the packet data network gateway to initiate to thepacket data network gateway to establish a connection, or, to establisha PMIP tunnel, or to assign care-of addresses for the terminal toperform client mobile IP protocol (CMIP) registration, such that a timedelay when a connection is established is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more better understood from thedetailed description given herein below for illustration only, and thusis not limitative of the present invention, and wherein:

FIG. 1 is a schematic structural view of an EPS;

FIG. 2 is a schematic structural view of a network system forestablishing a connection according to a first embodiment of the presentinvention;

FIG. 3 is a schematic structural view of obtaining information of apacket data network gateway according to an embodiment of the presentinvention;

FIG. 4 is a schematic structural view of obtaining information of apacket data network gateway according to another embodiment of thepresent invention;

FIG. 5 is a flow chart of a method for establishing a connectionaccording to a first embodiment of the present invention;

FIG. 6 is a flow chart of a method for establishing a connectionaccording to a second embodiment of the present invention;

FIG. 7 is a flow chart of a method for establishing a connectionaccording to a third embodiment of the present invention; and

FIG. 8 is a flow chart of a method for establishing a connectionaccording to a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention is illustrated in detail in the following withreference to the accompanying drawings and preferred embodiments.

FIG. 2 is a schematic structural view of a network system forestablishing a connection according to a first embodiment of the presentinvention. The system in the embodiment includes at least a mobilitymanagement entity 1, at least one serving gateway 2, and a packet datanetwork gateway 3.

The mobility management entity 1 is adapted to generate a create bearercontext request message and send the message to a selected servinggateway 2, wherein the create bearer context request message includes atleast address information of the specific packet data network gateway 3and indication information indicating the corresponding protocol type ofconnection establishment. In a specific implementation, the indicationinformation indicating the protocol type of connection establishment isused to indicate the protocol type of connection supported by thespecific packet data network gateway.

The serving gateway 2 is adapted to receive and analyze the createbearer context request message from the mobility management entity 1,and determine the protocol type of connection according to theindication information indicating the protocol type of connectionestablishment in the analyze result, and negotiate with the packet datanetwork gateway 3 to establish a connection by using the determinedconnection protocol.

In practical implementation, the mobility management entity 1 mayinclude a storage unit 12, a packet-data-network gateway-informationacquisition unit 10, a bearer-establishment initiation unit 14, and aresponse reception unit 16.

The storage unit 12 is adapted to store address information of at leastone packet data network gateway and indication information indicatingthe corresponding protocol type of connection establishment in advance(for example, the information may be manually configured). Theindication information indicating the protocol type of connectionestablishment is adapted to indicate the protocol type of connectionsupported by the packet data network gateway. The protocol type ofconnection is at least one of the GTP, the PMIP, and the CMIP. In otherembodiments, the storage unit may also be disposed in other networkentities, which will be discussed in detail in the following.

The packet-data-network gateway-information acquisition unit 10 isadapted to obtain address information of the specific packet datanetwork gateway and indication information indicating a correspondingprotocol type of connection establishment (for example, information ofthe protocol type of connection supported by the packet data networkgateway or information of the protocol type configured in advance). Suchinformation may be obtained from the storage unit 12.

The bearer-establishment initiation unit 14 is adapted to generate acreate bearer context request message and send the message to a selectedserving gateway. The create bearer context request message at leastcarries address information of at least one packet data network gatewayand indication information indicating the corresponding protocol type ofconnection establishment (for example, information of the protocol typeof connection supported by the packet data network gateway), and alsocarries a user equipment (UE) identifier, a context identifier of amobility management entity, and other bearer-related information. Eachof the indication information indicating the corresponding protocol typeof connection establishment may indicate that one or more types ofconnection protocol (for example, the GTP, the PMIP, and the GTP/PMIP)are available.

The response reception unit 16 is adapted to receive the create bearercontext request response message from the serving gateway 2.

The serving gateway 2 includes a reception and analysis unit 20, aprotocol type determination unit 22, a bearer-establishment process unit24, and a response process unit 26.

The reception and analysis unit 20 is adapted to receive and analyze thecreate bearer context request message from the mobility managemententity 1, so as to obtain address information of the packet data networkgateway and indication information indicating the corresponding protocoltype of connection establishment (for example, information of theprotocol type of connection supported by the packet data networkgateway), and some other related information.

The protocol type determination unit 22 determines one of the types ofconnection protocol (for example, the GTP or the PMIP) as a protocoltype of connection for establishing a connection with the packet datanetwork gateway according to an analyzed result of the reception andanalysis unit 20.

The bearer-establishment process unit 24 is adapted to process thecreate bearer context request message correspondingly according to theprotocol type of connection determined by the protocol typedetermination unit 22. Specifically, the corresponding process isdescribed as follows. If the determined protocol type of connection isthe GTP, the create bearer context request information is forwarded tothe packet data network gateway, and a connection with the packet datanetwork gateway is established. Or, if the determined protocol type ofconnection is the PMIP, a corresponding PMIP-binding update message issent to the packet data network gateway, so as to establish a PMIPtunnel between the serving gateway and the packet data network gateway.Or, if the determined protocol type of connection is the CMIP, a care-ofaddress is assigned and sent to the user terminal for the user terminalto perform CMIP registration.

The response process unit 26 is adapted to receive a response messagefrom the packet data network gateway for processing (for example,returning a response to the mobility management entity 1).

In an embodiment of the present invention, the protocol typedetermination unit 22 may further include a determination unit and aselection unit.

The determination unit is adapted to determine whether the servinggateway 2 supports the protocol type of connection in the indicationinformation indicating the protocol type of connection establishmentthat is analyzed by the reception and analysis unit.

The selection unit is adapted to select one protocol type of connectionthat is supported according to the determination result and determinethat such a protocol type of connection is the one that the servinggateway will use. For example, when the indication information in therequest message from the mobility management entity 1 indicates that oneprotocol type of connection is supported by the packet data networkgateway, and the determination unit determines that the serving gateway2 also supports the protocol type of connection, the connection protocolis the determined protocol type of connection. When the indicationinformation indicates that a plurality of types of connection protocolis supported by the packet data network gateway, the protocol type ofconnection supported by the serving gateway 2 is preferably selected asthe determined protocol type of connection. If the serving gateway 2supports all these types of connection protocol, one of the types (forexample, randomly, or the first one) is selected as the determinedconnection protocol type.

In the embodiments above, the information of the packet data networkgateway related to that a UE requests to establish a connection(information of address and the supported types of connection protocol)is stored in the mobility management entity 1 in advance. The presentinvention is not limited thereto, and the information may also beobtained from other places.

FIG. 3 is a schematic structural view of obtaining information of apacket data network gateway according to an embodiment of the presentinvention. The information of the packet data network gateway may bestored in an HSS 4. The mobility management entity 1 may communicatewith the HSS 4 through an S_(6a) interface to obtain the information. Ina practical implementation, the HSS 4 may include an HSS storage unit 42and a packet data network gateway information delivery unit 40.

The HSS storage unit 42 is adapted to store information of a packet datanetwork gateway corresponding to a subscriber (for example, addressinformation and information of its supported protocol type ofconnection). The information of the packet data network gateway iscorrelated to access point names (APNs). Each APN corresponds toinformation of a plurality of packet data network gateways.

The packet data network gateway information delivery unit 40 is adaptedto send the information of the packet data network gateways that themobility management entity 1 requires to the mobility management entity1 according to the user subscription information and other affiliatedrules.

In addition, the information of the packet data network gateway that themobility management entity 1 requires may come from a DNS server. Forexample, in other embodiments, a DNS server 5 may be further included. ADNS storage unit 50 of the DNS server 5 stores information ofcorresponding packet data network gateways (address information andinformation of its supported protocol type of connection). Theinformation of the packet data network gateway is correlated to APNs.Each APN may correspond to information of a plurality of packet datanetwork gateways.

The HSS 4 further includes a query unit 44, which is adapted to send aDNS query request (for example, carrying APN information) to the DNSserver 5, and receive query result from the DNS server 5. The HSS 4 maystore the query results, or provide the query results to the mobilitymanagement entity 1.

The packet-data-network gateway-information acquisition unit 10 isadapted to obtain address information of the specific packet datanetwork gateway and indication information indicating a correspondingprotocol type of connection establishment. For example, the informationdelivered from the packet-data-network gateway-information delivery unit40 may be received.

FIG. 4 is a schematic structural view of obtaining information of apacket data network gateway according to another embodiment of thepresent invention. In the embodiment, the mobility management entity 1may query the DNS server 5 directly for the required information of apacket data network gateway. In practical implementation, a queryrequest may be sent to the DNS server 5 through a query unit 100 in thepacket-data-network gateway-information acquisition unit 10. The queryrequest carries APN information. The DNS server 5 returns the queriedinformation of the packet data network gateway corresponding to the APNto the mobility management entity 1.

Implementation processes of the embodiments of the present invention areillustrated in the following with reference to FIGS. 5-8.

FIG. 5 is a flow chart of a method for establishing a connectionaccording to a first embodiment of the present invention.

In Step S70, the mobility management entity 1 obtains (for example, fromits own storage unit) an address of a specific packet data networkgateway and the protocol type of connection supported by the packet datanetwork gateway (such as the GTP, the PMIP, and the GTP/PMIP). A createbearer context request message including the above-mentioned informationis generated, and the request message is sent to one selected servinggateway. Illustrations are provided in the following taking the protocoltype of connection supported by the packet data network gateway beingGTP/PMIP as an example, that is, the packet data network gatewaysupports two types of connection protocol at the same time.

It should be noted that, the request message may include a plurality ofaddresses of the packet data network gateway, and each packet datanetwork gateway needs to correspond to its supported protocol type ofconnection.

In Step S52, the selected serving gateway receives the create bearercontext request message, analyzes the information in the requestmessage, and determines a protocol type of connection used to establisha connection with the packet data network gateway.

From the request message, the serving gateway analyzes the address ofthe packet data network gateway, the protocol type of connectionsupported by the packet data network gateway supports being GTP/PMIP,and some other information.

The serving gateway determines whether the serving gateway supports thetwo connection protocols or not. If only one of the two is supported, itis determined that the supported connection protocol serves as theprotocol type of connection for negotiating a connection with the packetdata network gateway. If both the two are supported, one of the two isselected (for example, the GTP) and determined to be the protocol typeof connection for negotiating a connection with the packet data networkgateway.

In Step S54, the serving gateway performs corresponding process with thepacket data network gateway according to the selected connectionprotocol, for example, connection negotiation. The process is describedas follows.

(1) If the serving gateway selects the GTP, the following process is asfollows.

The serving gateway creates one entry in its own EPS bearer table, sendsa create bearer context request message to the packet data networkgateway, and carries in the request message a user-plane addressassigned by the serving gateway, a user-plane tunnel endpoint identifier(TEID) of the serving gateway, and a control-plane TEID of the servinggateway;

The packet data network gateway returns a create bearer context responsemessage to the serving gateway, and carries in the response message auser-plane address of the packet data network gateway, a user-plane TEIDof the packet data network gateway, and an IP address that the packetdata network gateway assigns to the UE.

(2) If the serving gateway selects a PMIP, the following process is asfollows.

The serving gateway creates one entry in its own EPS bearer table, sendsa PMIP-binding update request message to the packet data networkgateway, and carries in the request message information related toestablishing a PMIP tunnel.

The packet data network gateway returns a PMIP-binding update responsemessage to the serving gateway, and carries an IP address assigned bythe packet data network gateway to the UE in the response message.

In Step S56, the serving gateway returns a create bearer contextresponse message to the mobility management entity, and carries in theresponse message information such as an IP address of the UE, a useraddress of the serving gateway, and a user-plane TEID of the servinggateway.

Until now, the process of bearer establishment is completed.

FIG. 6 is a flow chart of a method for establishing a connectionaccording to a second embodiment of the present invention. In thisembodiment, a UE adopts a CMIP as a mobility management protocol. Theflow includes the following steps.

In Step S61, the UE may report a CMIP capacity to a mobility managemententity in an access request (for example, attached request). The step isoptional.

In Step S62, an authentication process is performed among the mobilitymanagement entity, an HSS and the UE.

In Step S63, in a location registration process, the mobility managemententity may obtain subscription data of the UE from the HSS. Thesubscription data includes information of a packet data network gateway.

In Step S64, when the mobility management entity determines that the UEneeds to use a CMIP manner to establish a connection with the packetdata network gateway. The mobility management entity selects one servinggateway having an IP address assignment capacity, and sends a createbearer context request to the selected serving gateway. The mobilitymanagement entity carries related type indication information in thecreate bearer context request to inform the serving gateway. The UE usesthe CMIP manner. In practical application, the type indicationinformation may be, for example, requesting the serving gateway toassign one local IP address (for the UE to perform CMIP registrationwith the packet data network). Alternatively, the mobility managemententity may not carry the address of the packet data network gateway inthe create bearer context request message (that is, the address of thepacket data network gateway is null), and which serves as the typeindication information.

In Step S65, after receiving the create bearer context request, theserving gateway analyzes the type indication information and learns thatthe UE needs to use a CMIP to establish a connection with the packetdata network gateway. The CMIP protocol is determined as the protocoltype of connection for negotiating a connection with the packet datanetwork gateway. And, a local address is assigned, and the address isprovided to the mobility management entity in a create bearer contextresponse message.

In Step S66, a wireless bearer is established between the mobilitymanagement entity and a base station as well as between the mobilitymanagement entity and the UE. The mobility management entity sends tothe UE the local address assigned by the serving gateway. At the sametime, an address of the packet data network gateway (or information ofthe packet data network gateway obtained from the HSS by the mobilitymanagement entity) analyzed by the mobility management entity may alsobe sent to the UE. The step of sending the address or information of thepacket data network gateway is optional.

In Step S67, the UE initiates a CMIP connection establishment flow tothe packet data network gateway. The address of the packet data networkgateway may be obtained through a DNS process performed by the UE on theinformation of the packet data network gateway, or may also be obtaineddirectly from the mobility management entity.

FIG. 7 is a flow chart of a method for establishing a connectionaccording to a third embodiment of the present invention.

In Step S70, an HSS provides APNs and information of correspondingpacket data network gateway (for example, an address, a protocol type ofconnection that the packet data network gateway supports) to a mobilitymanagement entity according to the user subscription information andother affiliated rules. The protocol type of connection may be the GTP,the PMIP, and the GTP/PMIP. When a plurality of addresses of the packetdata network gateway is sent to the mobility management entity by theHSS, each packet data network gateway address needs to correspond to oneprotocol type of connection.

The step may be executed in the step that the HSS insert userinformation into the mobility management entity.

Steps S72 to S78 in the following are similar to Steps S50 to S56 inFIG. 5 in principle, which are not repeated here.

FIG. 8 is a flow chart of a method for establishing a connectionaccording to a fourth embodiment of the present invention.

In Step S80, the mobility management entity initiates a query to a DNSserver, carries APNs in the query request for the DNS server to searchfor information of the corresponding packet data network gateway.

In Step S81, the DNS server returns the searched information of thepacket data network gateway to the mobility management entity, that is,an address of a packet data network gateway and a protocol type ofconnection that the packet data network gateway supports. The protocoltype of connection may be the GTP, the PMIP, and the GTP/PMIP. When aplurality of addresses of the packet data network gateway is returned tothe mobility management entity by the DNS server, each address of thepacket data network gateway needs to correspond to one protocol type ofconnection.

Steps S82 to S85 in the following are similar to Steps S52 to S56 inFIG. 5 in principle, which are not repeated here.

In addition, in other embodiments of the present invention, the methodmay also be implemented with the following process. First, an HSS mayquery a DNS server for information of a corresponding packet datanetwork gateway. The HSS then provides the queried information of thepacket data network gateway to a mobility management entity. Themobility management entity may initiate a create bearer context requestmessage by using the packet data network gateway information. Thefollowing steps are similar to those in the embodiments above.

In view of the above, in the embodiments of the present invention, whenthe serving gateway requests the mobility management entity to establisha connection, a protocol type of connection supported by the packet datanetwork gateway is indicated. In this way, the serving gateway may use asuitable (that the packet data network gateway supports) connectionprotocol to initiate establishment of a connection with the packet datanetwork gateway, or establish a PMIP tunnel between the serving gatewayand the packet data network gateway, or assign a care-of address for auser terminal to perform CMIP registration, so as to reduce a time delaywhen a connection is established.

It is apparent to those of ordinary skill in the art that all or a partof steps in the above method embodiments may be accomplished by relevanthardware that is instructed through a program. The program may be storedin a computer-readable storage medium. When the program is executed, thesteps of the above method embodiments may be performed. The storagemedium may be a magnetic disk, an optical disk, a read-only memory(ROM), or a random access memory (RAM).

The above descriptions are merely preferred embodiments of the presentinvention, but not intend to limit the scope of the present invention.Any modification, equivalent replacement, and improvement made withoutdeparting from the spirit and principle of the present invention fallwithin the scope of the present invention.

1. A method for establishing a connection, comprising: generating acreate bearer context request message; sending the create bearer contextrequest message to a selected serving gateway, wherein the create bearercontext request message comprises address information of at least onepacket data network gateway and corresponding indication information ofthe protocol type of connection establishment.
 2. The method accordingto the claim 1, further comprising obtaining the address information ofthe packet data network gateway and the corresponding indicationinformation of the protocol type of connection establishment.
 3. Themethod according to the claim 2, wherein the process of obtaining theaddress information of the packet data network gateway and thecorresponding indication information of the protocol type of connectionestablishment comprises: obtaining the address information of the packetdata network gateway and the corresponding indication information of theprotocol type of connection establishment from a storage unit located inat least one of a Home Subscriber Server (HSS), a Domain Name Service(DNS) Server, and a Mobility Management Entity, wherein the indicationinformation indicates a protocol type of connection establishmentsupported by the packet data network gateway, and the protocol type ofconnection establishment is selected from a group of a General PacketRadio Service Tunneling Protocol (GTP), a Proxy Mobile IP Protocol(PMIP), and a Client Mobile IP Protocol (CMIP).
 4. A method forestablishing a connection, comprising: receiving and parsing a createbearer context request message, and obtaining the address information ofa packet data network gateway and corresponding indication informationof a protocol type of connection establishment; determining a protocoltype of connection for establishing a connection with the packet datanetwork gateway according to the analyzed indication information of theprotocol type of connection establishment; and processing the createbearer context request message according to the determined protocol typeof connection.
 5. The method according to claim 4, wherein the processof determining the protocol type of connection for establishing aconnection with the packet data network gateway according to theanalyzed indication information indicating the protocol type ofconnection establishment comprises: determining whether the protocoltype of connection in the indication information is supported by aserving gateway; selecting the protocol type of connection supported bythe serving gateway for the serving gateway to use, wherein the protocoltype of connection comprises at least one of a GTP, a PMIP, and a CMIP.6. The method according to claim 5, wherein the process of processingthe create bearer context request message according to the determinedprotocol type of connection comprises: forwarding the create bearercontext request information to the packet data network gateway if thedetermined protocol type of connection is a GTP; sending, by the servinggateway, a corresponding PMIP-binding update message to the packet datanetwork gateway if the determined protocol type of connection is a PMIPand establishing a PMIP tunnel between the serving gateway and thepacket data network gateway; assigning and sending a care-of address tothe user terminal to perform a CMIP registration if the determinedprotocol type of connection is a CMIP.
 7. A method for establishing aconnection, implemented in a system comprising at least a mobilitymanagement entity, a serving gateway, and a packet data network gateway,comprising: generating, by the mobility management entity, a createbearer context request message and sending the request message to aselected serving gateway, wherein the create bearer context requestmessage comprises address information of at least one packet datanetwork gateway and corresponding indication information of a protocoltype of connection establishment; parsing, by the serving gateway, thecreate bearer context request message, and determining a protocol typeof connection for establishing a connection with the packet data networkgateway according to the indication information indicating the protocoltype of connection establishment; and processing, by the servinggateway, the create bearer context request message correspondinglyaccording to the determined protocol type of connection.
 8. The methodaccording to claim 7, wherein the process of determining the protocoltype of connection for establishing a connection with the packet datanetwork gateway according to the indication information comprises:determining whether the protocol type of connection in the indicationinformation is supported by the serving gateway; and selecting theprotocol type of connection supported by the serving gateway for theserving gateway to use.
 9. The method according to claim 7, wherein theprocess of processing the create bearer context request messagecorrespondingly according to the determined protocol type of connectioncomprises: forwarding the create bearer context request information tothe packet data network gateway if the determined protocol type ofconnection is a GTP; sending, by the serving gateway, a correspondingPMIP-binding update message to the packet data network gateway andestablishing a PMIP tunnel between the serving gateway and the packetdata network gateway if the determined protocol type of connection is aPMIP; and assigning and sending a care-of address to the user terminalfor the user terminal to perform CMIP registration if the determinedprotocol type of connection is a CMIP.
 10. A mobility management entity,comprising: a packet data network gateway information acquisition unit,adapted to obtain address information of the packet data network gatewayand corresponding indication information of the protocol type ofconnection establishment; and a bearer establishment initiation unit,adapted to generate a create bearer context request message and send themessage to a selected serving gateway, wherein the create bearer contextrequest message comprises address information of at least one packetdata network gateway and the indication information.
 11. The mobilitymanagement entity according to claim 10, wherein the indicationinformation is adapted to indicate the protocol type of connectionestablishment supported by the packet data network gateway, and theprotocol type of connection establishment is selected from a group of aGTP, a PMIP, and a CMIP.
 12. The mobility management entity according toclaim 10, further comprising: a storage unit, adapted to store addressinformation of at least one packet data network gateway andcorresponding indication information of the protocol type of connectionestablishment.
 13. The mobility management entity according to claim 10,wherein the packet data network gateway information acquisition unitfurther comprises a query unit, adapted to send a query request to aDomain Name Service (DNS) Server, and obtain the address information ofthe packet data network gateway and the indication information.
 14. Aserving gateway, comprising: a reception and analysis unit, adapted toreceive and analyze a create bearer context request message, and obtainaddress information of a packet data network gateway and correspondingindication information of a protocol type of connection establishment; aprotocol type determination unit, adapted to determine a protocol typeof connection for establishing the connection with the packet datanetwork gateway according to an analyzed result of the reception andanalysis unit; and a bearer establishment process unit, adapted toprocess the create bearer context request message according to theprotocol type of connection determined by the protocol typedetermination unit.
 15. The serving gateway according to claim 14,wherein the protocol type determination unit further comprises: adetermination unit, adapted to determine whether the protocol type ofconnection in the indication information is supported by the servinggateway; and a selection unit, adapted to select one protocol type ofconnection supported by the serving gateway for the serving gateway touse, wherein the selected protocol type of connection is one of a GTP, aPMIP, and a CMIP.
 16. The serving gateway according to claim 15,wherein: the bearer-establishment process unit forwards the createbearer context request information to the packet data network gatewayand establishes a connection with the packet data network gateway, ifthe protocol type of connection determined by the protocol typedetermination unit is the GTP; the bearer-establishment process unitsends a corresponding PMIP-binding update message to the packet datanetwork gateway and establishes a PMIP tunnel between the servinggateway and the packet data network gateway, if the protocol type ofconnection determined by the protocol type determination unit is thePMIP; and the bearer-establishment process unit assigns and sends acare-of address to the user terminal for the user terminal to performCMIP registration, if the protocol type of connection determined by theprotocol type determination unit is the CMIP.
 17. A network system,comprising at least a mobility management entity, a serving gateway, anda packet data network gateway, wherein: the mobility management entityis adapted to generates a create bearer context request message and sendthe message to a selected serving gateway, wherein the create bearercontext request message comprises at least address information of thepacket data network gateway and corresponding indication information ofthe protocol type of connection establishment; and the serving gatewayis adapted to analyze the create bearer context request message from themobility management entity, determine the protocol type of connectionfor establishing a connection with the packet data network gatewayaccording to the indication information, and process the create bearercontext request message according to the determined protocol type ofconnection.
 18. The network system according to claim 17, wherein theserving gateway further comprises: a determination unit, adapted todetermine whether the protocol type of connection in the indicationinformation is supported by the serving gateway; and a selection unit,adapted to select one protocol type of connection supported by theserving gateway for the serving gateway to use.
 19. The network systemaccording to claim 17, further comprising at least one of: a HomeSubscriber Server HSS, adapted to store at least one address of thepacket data network gateway and corresponding indication information ofthe protocol type of connection establishment; and a Domain Name ServiceServer, DNS server, adapted to store at least one address of the packetdata network gateway and corresponding indication information of theprotocol type of connection establishment; wherein, the mobilitymanagement entity comprises a packet data network gateway informationacquisition unit, adapted to obtain address information of the packetdata network gateway and corresponding indication information of theprotocol type of connection establishment from one of the HSS and theDNS server, wherein the indication information is adapted to indicatethe protocol type of connection supported by the packet data networkgateway.
 20. The network system according to claim 18, furthercomprising at least one of: a Home Subscriber Server HSS, adapted tostore at least one address of the packet data network gateway andcorresponding indication information of the protocol type of connectionestablishment; and a Domain Name Service (DNS) server, adapted to storeat least one address of the packet data network gateway andcorresponding indication information of the protocol type of connectionestablishment; wherein, the mobility management entity comprises apacket data network gateway information acquisition unit, adapted toobtain address information of the packet data network gateway andcorresponding indication information of the protocol type of connectionestablishment from one of the HSS and the DNS server, wherein theindication information is adapted to indicate the protocol type ofconnection supported by the packet data network gateway.